Changeset 538 in xtideuniversalbios for trunk/XTIDE_Universal_BIOS/Src/Device/IDE

Timestamp:

Apr 11, 2013, 8:05:27 PM (12 years ago)

Author:

aitotat@…

google:author:

aitotat@gmail.com

Message:

Changes to XTIDE Universal BIOS:

• Segment overflow is now checked when transfer buffer pointer is normalized (AT builds only).

Location:

trunk/XTIDE_Universal_BIOS/Src/Device/IDE

Files:

• IdeTransfer.asm (modified) (6 diffs)
• JrIdeTransfer.asm (modified) (2 diffs)

trunk/XTIDE_Universal_BIOS/Src/Device/IDE/IdeTransfer.asm

@@ -78 +78 @@
     mov     bx, g_rgfnPioRead
     call    InitializePiovarsInSSBPwithSectorCountInAH
+%ifdef USE_AT
+    jc      SHORT ReturnWithTransferErrorInAH
+%endif
 
     ; Wait until drive is ready to transfer
@@ -154 +157 @@
     mov     bx, g_rgfnPioWrite
     call    InitializePiovarsInSSBPwithSectorCountInAH
+%ifdef USE_AT
+    jc      SHORT ReturnWithTransferErrorInAH
+%endif
 
     ; Always poll when writing first block (IRQs are generated for following blocks)
@@ -201 +207 @@
 ;       SS:BP:  Ptr to PIOVARS
 ;   Returns:
-;       Nothing
-;   Corrupts registers:
-;       AX, BX, DX
+;       ES:SI:  Normalized pointer
+;       AH:     INT 13h Error Code (only when CF set)
+;       CF:     Set of failed to normalize pointer (segment overflow)
+;               Cleared if success
+;   Corrupts registers:
+;       AL, BX, DX
 ;--------------------------------------------------------------------
 ALIGN JUMP_ALIGN
@@ -209 +218 @@
     ; Store sizes and Data Port
     mov     [bp+PIOVARS.bSectorsLeft], ah
+%ifdef USE_AT
+    xchg    dx, ax
+%endif
     mov     ax, [di+DPT.wBasePort]
     mov     [bp+PIOVARS.wDataPort], ax
@@ -280 +292 @@
     ;------------------------------------
 %endif                  ; 26    29/26
+    clc
     ret
 %endif ; MODULE_8BIT_IDE_ADVANCED
@@ -288 +301 @@
 ; IdeTransfer_NormalizePointerInESSI
 ;   Parameters:
+;       DH:     Number of sectors to transfer (when USE_AT defined)
 ;       ES:SI:  Ptr to be normalized
 ;   Returns:
 ;       ES:SI:  Normalized pointer (SI = 0...15)
+;       AH:     INT 13h Error Code (only when CF set)
+;       CF:     Set of failed to normalize pointer (segment overflow)
+;               Cleared if success
 ;   Corrupts registers:
 ;       AX, DX
 ;--------------------------------------------------------------------
 IdeTransfer_NormalizePointerInESSI:
+; Normalization can cause segment overflow if it is done when not needed
+; (I don't know if any software calls with such seg:off address).
+; This does not apply to XT systems since nothing will write to main BIOS ROM.
+; On AT systems things are quite different, even in protected mode the address
+; is passed in seg:offset form and HMA is accessible in real mode.
+%ifdef USE_AT
+    xor     dl, dl
+    shl     dx, 1
+    dec     dx      ; Prevents normalization when bytes + offset will be zero
+    add     dx, si
+    jc      SHORT .NormalizationRequired
+    ret
+.NormalizationRequired:
+%endif ; USE_AT
+
     NORMALIZE_FAR_POINTER   es, si, ax, dx
-    ret
+%ifdef USE_AT       ; CF is always clear for XT builds
+    mov     ah, 0   ; Clear AH and preserve CF
+    rcl     ah, 1   ; RET_HD_INVALID
+%endif
+    ret
+
 
 

trunk/XTIDE_Universal_BIOS/Src/Device/IDE/JrIdeTransfer.asm

@@ -53 +53 @@
     xor     ax, ax
     mov     [bp+MEMPIOVARS.bSectorsDone], al
-    mov     al, [bp+IDEPACK.bSectorCount]
-    mov     [bp+MEMPIOVARS.bSectorsLeft], al
+    mov     dh, [bp+IDEPACK.bSectorCount]
+    mov     [bp+MEMPIOVARS.bSectorsLeft], dh
     mov     al, [di+DPT_ATA.bBlockSize]
     mov     [bp+MEMPIOVARS.wSectorsInBlock], ax
@@ -62 +62 @@
     ; Normalize pointer
     call    IdeTransfer_NormalizePointerInESSI
+%ifdef USE_AT
+    jc      SHORT ReturnWithMemoryIOtransferErrorInAH
+%endif
 
     ; Get far pointer to Sector Access Window